In a coal gasification plant a pulverised carbonaceous fuel, such as coal, is transformed into a product gas consisting mainly of synthesis gas. The gasification plant typically comprises a gasifier apparatus comprising a gasification reactor wherein the pulverised carbonaceous fuel is gasified under high pressure and high temperature conditions. In such a gasifier apparatus, a wall surface is provided on which a slag can form out of the ashes. Such a wall surface can be provided in the form of a membrane wall such as described in for instance patent specification GB 1 501 284.
The slag is allowed to drip down along the wall surface, to a slag discharge opening or slag tap, where the slag is allowed to fall freely into a slag water bath where it can cool and solidify. This is described in, for instance, U.S. Pat. No. 4,852,997. Other gasification reactors are described in e.g. U.S. Pat. No. 4,436,530, DE 41 09 063 and U.S. Pat. No. 5,976,203.
The gasifier reactor described in mentioned U.S. Pat. No. 4,852,997 is provided with a skirt in the form of a hooded element around the area where the slag falls down from the slag tap. The skirt has a lower conical part, diverging when considered from top to bottom, and ending in a spray ring. The spray ring is functional to spray water on the slag bath to wet the slag floating on the slag bath water surface.
The skirt shown in mentioned U.S. Pat. No. 4,852,997 suffers from various problems. Since the free falling slag is molten and has a high temperature, the skirt is exposed to overheating damage.
It is an object of the present invention to minimise the above problem.
It is a further object to provide an alternative apparatus for gasifying a fuel.